The neonatal puppy responds to hemorrhage with a decrease in cardiovascular function and severe metabolic acidosis. Sodium bicarbonate increases pH and improves cardiovascular function. The purpose of this study was to determine if the correction of the acidosis by sodium bicarbonate was responsible for the improved cardiovascular function since sodium bicarbonate, in addition to being a buffer, has a high sodium concentration and osmolality.
A solution of sodium chloride having the same osmolality as sodium bicarbonate, one having the same sodium concentration as sodium bicarbonate, and a mannitol solution with the same osmolality as sodium bicarbonate all produced improved cardiovascular function without a pH rise. This suggests that improved cardiovascular function after sodium bicarbonate infusion may be due to the osmolality of the solution rather than its buffering action.